1. Field of the Invention
This invention relates to the field of self-erecting windmills used to extract the power from the wind.
2. Prior Art
Windmills are the most commonly known devices to utilize the motion of air to effectuate a rotary motion in the production of useful energy. In the prior art, it is well known that the use of fixed site, horizontal or vertically in placed windmills have received the most consideration. These devices, as typified by the Hallady-Perry windmill design of the 1920's and 1930's, have been used conventionally either to drive pumps for the extraction of water from subsurface locations or, for the generation of electricity. The refinement of such devices today as a result of current societal demands to find alternative techniques for the generation of energy has become an object of technological research and inquiry. The prior art is replete with attempts to improve the efficiency of various windmill components, such as blades, bearings and reduction gears to reduce the cost of such windmill designs while effectuating a modest increase in output. Current attempts at optimizing windmill design center around vast size increases with the use of current technology to minimize moments of inertia and frictional forces existing in such large systems. One reason for the dramatic increase in research, vis-a-vis orders of magnitude larger windmill devices is the known gradient of windspeed as a function of height above the surface. It is well established that the speed of the wind increases substantially at heights approximately 50 to 75 feet above ground level due to factors of ground turbulance, wind sheer and the existence of steady state conditions above localized obstructions which allow continuous motion of the air thereby permitting steady state wind conditions at speeds much higher than ground conditions. In a very crude sense, this can be noticed in the performance of sailboats, wherein on very calm periods those craft with very tall masts are able to move through the action of wind approximately 50 feet above sea level while smaller craft with smaller masts are unable to generate any motion as a result of the lack of wind closer to the water's surface. Accordingly, it becomes an important consideration in the effective utilization of any windmill system that it be located at a sufficient height above the ground so as to receive a stronger and steadier flow of air.
Were it possible to build a tower 1,000 feet or more high another advantage would accrue. At these heights the nighttime drop in wind speed is far less than near the surface, and the windmill would become a steadier and more reliable source of power.
The prior art attempted to achieve this condition by the use of large towers upon which the windmills were placed. Even today, with contemporary research, the use of large towers supporting large blades appears to be one viable alternative to the problem of locating the windmill above ground level.